1. Field of the Invention
The present invention relates to oil and/or gas well production. More particularly, the present invention relates to an improved method and apparatus for producing oil and gas from a well using a vacuum or pressure reducing system to reduce the pressure at the wellhead and imposes a lower pressure at the oil and/or gas producing formation. This can be applied to wells under secondary production methods to increase the secondary method efficiency. It can also be applied to naturally flowing wells to reduce the pressure in the casing at the producing formation.
2. General Background of the Invention
Two patents have issued that are directed to use of a vacuum pump at the top of the well. The first example of such a system is described in the Blanchard et al. patent, U.S. Pat. No. 5,400,858 entitled “Groundwater Recovery System”. This patent describes a system for recovering groundwater from a subterranean aquifer by connecting a vacuum pump at the top of the well tubing. Gas from the annular area mixes through apertures in the tubing with the liquid, thus reducing the density of the flowing liquid and aiding in the lift. The Blanchard patent is focused on groundwater recovery only.
U.S. Pat. No. 5,547,021 issued to Dennis P. Raden and entitled “Method and Apparatus for Fluid Production From a Wellbore” describes a system for assisting in lifting produced hydrocarbon liquid and produced water by means of a vacuum applied to the top of the production tubing; in addition, this method could be supplemented by providing a lift gas fed from another production tubing to the bottom of the well. This lift gas could also be supplied by delivering down the well casing or the casing/tubing annulus. He also claims usage of eductors and valves. The Raden patent claims the vacuum applied at the ground surface is imposed through the tubing string and into the sump at the bottom of the well.